Device for processing photographic material

ABSTRACT

In a wet processing apparatus for photographic material wherein the material is guided at least partially through and out of a body of processing liquid by a guide plate having a grooved surface and extending upwardly from below the liquid level to an egress end above the liquid level, a plurality of openings are formed in the plate intermediate the liquid level and egress end, with each opening communicating with at least one groove, to permit the overflow of the liquid therethrough. Preferably, an anti-siphon passageway connects each such opening with the atmosphere.

United States Patent 1 1 Stievenart et a1.

1111 3,733,992 1 51 May 22,1973

[54] DEVICE FOR PROCESSING PI-IOTOGRAPHIC MATERIAL [75] Inventors: Emile Frans Stievenart, I-loboken; Herman Fernand Verbruggen, Bercham, both of Belgium [73] Assignee: Agfa-Gevaert N.V., Mortsel, Belgi- [22] Filed: Sept. 1, 1971 [21] Appl. No.: 177,022

[30] Foreign Application Priority Data Feb. 19, 1971 Great Britain ..42,015/70 52 us. 01. ..95/94 R [51] Int. Cl. ..G03d 3/12 [58] Field of Search ..95/89 R, 94 R, 95, 95/96 [56] References Cited UNITED STATES PATENTS 3,137,225 6/1964 Cuthbert ..95/89 R 3,263,590 8/1966 Wanielista et al .....95/89 R x 3,283,689 11/1966 Carlson ..95/89 R 3,107,596 10/1963 Arnold et al.

3,635,144 l/1972 Beck ..95/95 FOREIGN PATENTS OR APPLICATIONS 1,218,312 1/1971 Great Britain ..95/89 R Primary Examiner.1ohn M. Horan Assistant ExaminerFred L. Braun Attorney-William J. Daniel [57] ABSTRACT In a wet processing apparatus for photographic material wherein the material is guided at least partially through and out of a body of processing liquid by a guide plate having a grooved surface and extending upwardly from below the liquid level to an egress end above the liquid level, a plurality of openings are formed in the plate intermediate the liquid level and egress end, with each opening communicating with at least one groove, to permit the overflow of the liquid therethrough. Preferably, an anti-siphon passageway connects each such opening with the atmosphere.

13 Claims, 15 Drawing Figures PATENIE M22 1973 SHEET 2 UF 6 PATENTEB MAY 2 2 I975 SHEET 4 0F 6 PATENTEI] HAY 2 2 I975 SHEET 6 UF 6 Iii DEVICE FOR PROCESSING PHOTOGRAPHIC MATERIAL The present invention relates to a photographic processing apparatus, and in particular to a processing apparatus comprising a container for holding processing liquid and a guide plate having a concave surface which determines the path of a sheet of photographic material through the processing liquid in the container.

The invention is particularly but not exclusively concerned with apparatus for use in the automatic and rapid development processing of light-sensitive or X-ray sensitive photographic films or sheets after exposure. The invention can also be used in the constructing apparatus for automatically conducting photographic material through stabilizing, fixing and/or rinsing baths, e.g., in apparatus for use in processing image-wise exposed silver halide material by a process as disclosed in Belgian Pat. specification No. 722,148 filed Oct. 11, 1968 and relating to a method of producing photographic images, wherein the material is conveyed at substantially constant speed through activating, stabilizing, fixing and rinsing stations in succession.

It is often necessary in the automatic processing of photographic materials to renew the processing liquid at a rate proportional to its use or exhaustion. It has been proposed to provide means for scanning the width and length of film or paper sheets as they are conveyed into a processing bath and to introduce fresh liquid into the apparatus in an amount proportional to the area of the photographic material, a corresponding quantity of used liquid being discharged as overflow. This system of automatic replenishment requires numerous electrical components such as microswitches and electromagnetic valves, which require regular maintenance and adjustment.

It has also been proposed to discharge liquid from the container by squeezing off the liquid which adheres to the surfaces of a processed sheet and by collecting said liquid in a separate container and by introducing fresh liquid into the container by means of a system which is responsive to the level of the liquid in the container, e.g. by means of 21 birds fountain system. This proposal has the advantage that the processing apparatus can be of very simple construction. However, it has been found that an insufficient proportion of the processing liquid which actually participates in the processing of the sheet is removed from the container.

The present invention aims at providing a photographic processing apparatus of simple construction and such that discharge of chemically exhausted liquid by the photographic sheet material as it is processed is promoted.

According to the present invention, an apparatus for processing photographic material comprises:

a. a container for holding processing liquid,

b. means for keeping said container filled with liquid up to a predetermined level, a guide plate having a concave surface for guiding photographic material into and out of such processing liquid, a plurality of grooves running along such concave surface and a series of openings providing liquid-overflow edges distributed across the path of the sheet material between said predeter mined level and the exit end of said guide plate, at least some of said grooves leading into openings thus provided,

d. means for driving sheet material through the container, and e. immersion means for constraining such sheet material to follow the said concave supporting surface of the guide plate at least over the part thereof which rises towards the exit end of the plate. When the apparatus as described hereinbefore is in operation, it may be observed that, as the leading edge of a moving sheet being processed emerges from the body of processing liquid in the container, the sheet draws or drags liquid upwardly along the grooves towards the exit end of the plate, and as aid liquid reaches the said liquid-overflow edges in the plate, the liquid drains through the said openings in the plate to a lower location where the liquid may be caught in a separate receptacle. The amount of processing liquid which leaves the container for each sheet of photographic material which is processed in the apparatus is therefore nearer to the amount of liquid which is actually used or chemically exhausted in the processing of the sheet, than it would be in the absence of the said openings in the plate.

The grooves in the concave surface of the guide plate may extend parallel with the line of motion of the photographic material along the plate or at an inclination to that line. The said grooves should preferably extend over at least the full length of that portion of the plate which lies below the said predetermined liquid level and such grooves should also extend some distance above the predetermined liquid level at the exit end of the guide plate. Preferably, the said grooves lead directly into the said openings; if they do not do so there should be some other form of communication e.g. shallower branch grooves, between the main grooves and such portions.

There should preferably be a pair of rollers just beyond the exit end of the container for squeezing liquid from the photographic material so that such liquid can be caught by a receptacle, e.g. by the same receptacle wherein the liquid which discharges through the guide plate openings is caught.

The guide plate openings providing the liquidoverflow edges may be in the form of holes which are wholly within the plate boundaries. Alternatively, said openings may be in the form of open-ended slots or recesses extending some distance along the plate from its exit end.

In the case that the openings are in the form of holes as aforesaid, there may be a tendency, when the trailing edge of the photographic material moves upwardly, clear of the holes, for processing liquid to carry on discharging over the liquid-overflow edges in the guide plate, from the body of liquid in the container, due to a syphon effect. This tendency has been noticed, e.g. when using developer solutions of rather low surface tension or rather high viscosity.

Any such tendency for excess discharge to occur can be avoided by providing air passages along the plate for ensuring that the holes communicate with the atmosphere at the exit end of the plate even when the holes are filled with liquid and the portion of the plate between such holes and the exit end of the plate is covered by a sheet material which is leaving the apparatus. For example, such air passages may take the form of surface grooves on the top or bottom side of the guide plate. An alternative way of avoiding such excess discharge of liquid is to make the plate openings (which provide the overflow edges) in the form of recesses or slots opening at the exit end of the plate as before referred to.

It has been shown that the described arrangement permits the atmosphere easily to rupture the bead of syphoning liquid and to cause thereby the arrestment of the discharge.

The invention will be further described hereinafter with reference to an apparatus for automatically processing photographic material wherein the material is conveyed at substantially constant speed through activating, stabilizing, fixing and rinsing stations in succession. It will be understood, however, that the apparatus according to the invention is not limited to this particular process, and thus it may also be used in the treatment of photographic sheet materials in other processing compositions which require the replacement of the liquid in the container by an amount of fresh liquid which is nearly proportional to the area of the sheet of material passed through the liquid.

Some embodiments of the present invention are described hereinafter with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a longitudinal section of an apparatus according to the present invention;

FIG. 2 is a perspective view of the apparatus according to FIG. 1, the lid and the supply bottles of the appa ratus being omitted,

FIG. 3 is a top view of an enlarged end portion of a concave guide plate of a container of the apparatus, and

FIG. 4 is a section on line 4-4 of FIG. 3, the immersion plate for a sheet of material being added to the figure,

FIG. 5 is a top view of an end portion of a concave guide plate, the grooves leading into the discharge holes through branch grooves,

FIG. 6 is a top view of an end portion of a guide plate which is provided with air passages in the form of openended slots, and

FIG. 7 is a section on line 77 of FIG. 6,

FIG. 8 is a top view of a portion of a concave guide plate wherein the slots are tapered towards the exit end,

FIG. 9 is a top view of a portion of a concave guide plate which is provided with air passages in the form of terminal grooves, and

FIG. 10 is a section on line 10-10 of FIG. 9,

FIG. 11 is a longitudinal section of another embodiment of a processing section of the apparatus according to the invention, and

FIG. 12 is a top view of an end portion of a concave guide plate of the embodiment according to FIG. 11, whereas FIG. 13 is a section on line l3l3 of FIG. 12,

FIG. 14 is a sectional view of a birds fountain system for controlling the level of the liquid in the apparatus,

FIG. 15 is a view of a detail of the coupling of the driving rollers of the apparatus with the driving mechamsm.

The apparatus 10 shown in FIG. 1 comprises a housing 22 with a lid 21. The housing has an inlet opening and an outlet opening 23 for the material to be processed whereas as intermediate opening 24 is provided in the lid 21 about halfway the path followed by the sheet material through the apparatus, and the purpose of this latter opening will be explained further in the description. Preferably the housing rests on three or four set screws for the horizontal adjustment of the apparatus.

The apparatus has four processing stations which are in succession: the activating station 25, the stabilizing station 26, the fixing station 27 and the rinsing station 28. Processing liquid is supplied to the different processing stations from inverted supply bottles 29 to 32 through a birds fountain level control which will be described in detail further in the description. The advance of a sheet through the apparatus is done by pairs of rollers, such as the rollers 33,- 34 and 35, 36 shown for the activating station 25. The rollers are covered with a resilient material such as butyl rubber or the like and they may be pressed against each other in a known way by means of elastic belts tensioned over the plastics roller bearings at each extremity of the roller shafts so as to hold the latter together. One extremity of each roller shaft extends at one side of the station and is provided with a two-pin coupling part 38 which may engage an Sshaped driving member 39 (FIG. 15) which is fitted to a driving shaft extending from a casing 40 (FIG. 2) wherein the electric driving motor of the apparatus and the gears through which the different driving shafts for the other stations are coupled to the motor, are located. It will be noted that, in addition to the pair of rollers at the outlet end of each station, the activating station 25 and the stabilizing station 26 also comprise a pair of rollers at the inlet end thereof. This is done for the following reason. The treatment of the material in these two stations is rather critical and therefore it is necessary to start and to arrest the treatment at a welldeterrnined locus. At the outlet end of the stations this is done by the pairs of rollers which squeeze off the liquid adhering to the processed sheet, whereas at the inlet end of the station this is done by the lower roller of the pair of rollers which dips into the processing liquid and which starts the wetting of the emulsion layer of the sheet, which is turned downwardly, at the nip of the rollers.

The container of one processing station, e. g. the activating station, will now be described in detail with reference to FIGS. 1 to 4. The container of the station 25 is formed by lateral side walls 46 and 47, a guide plate 48 for the sheet material, said guide platehaving towards the inlet end of the station'a flat portion 49 and a U-shaped portion50 which terminates in a vertical front wall 51, and a rear wall 52.

The container may be made of plastic such as hard PVC,- and it constitutes a rigid unit which can be vertically removed from the apparatus for cleaning purposes. In the operative position the container rests on elongate supports 53 at the innerside of the lateral walls of the apparatus.

Below the container, and supported on the bottom wall of the apparatus, there is a receptacle 54 in the form of a rectangular slide which covers the width of the processing station, and which is provided with a grip 55 in the form of a hollow transparent tube, the extremities of which communicate with the interior of the receptacle. The grip 55 permits to check the level of liquid received in the receptacle, and to remove the receptacle from the apparatus in order to pour out the waste liquid collected therein.

The U-shaped portion 50 of the container communicates with a holder 56 which comprises a circular collar 57 (FIG. 14) in which may fit the stopper 58 of an inv ing liquid in the container.

The height of the bottle is adjustable through spacer rings 63 which control the distance between a rim portion 64 of the stopper and the bottom wall 65 of a widened bore in the collar 57. The position of the bottle may be secured by a threaded ring 66 which may be screwed on the collar 57.

A detail of the concave portion of the guide plate 48 is shown in FIGS. 3 and 4. The concave surface of the guide plate is provided with grooves 67 which run generally from the inlet end of the plate, located at the right hand side of the figure, towards the outlet end of the plate. The grooves end at a locus which is between the exit end of the plate and the level of the liquid in the container which is indicated by the dashed line 69. The grooves 67 terminate in openings in the form of circular holes 70 which determine liquid-overflow edges 71 which are located between the level of the processing liquid and the exit end of the plate.

An immersion plate 72 constrains a sheet to be processed to follow the concave surface of the guide plate 48 at least over the part thereof which rises towards the exit end of the container. Preferably said immersion plate has ribs or other projections at its surface which contact the sheet constrained thereby in order to reduce the frictional contact with the sheet, and said ribs preferably cross the grooves in the lower plate 48.

The operation of the apparatus is as follows.

The different processing stations of the apparatus being provided with the corresponding processing liquids, the level of which is adjusted to be below the openings 70 in the different guide plates, and the driving rollers rotating at a constant peripheral speed, a

I photographic sheet, which for instance has been imagewise exposed, is introduced through the opening in the apparatus. The light-sensitive emulsion side of the sheet being turned downwardly, the development starts as soon as the sheet enters the nip between the rollers 33, 34 since the lower roller 34 is abundantly wetted with activating liquid. At some distance after the bite of the rollers, the immersion plate 72 dips the sheet into the liquid in the container and also constrains the sheet to follow a path which is close to and at the part rising towards the exit end, is in contact with, the concave surface of the guide plate. As the leading edge of the advancing sheet emerges from the processing liquid, liquid is drawn by the sheet in the grooves 67 by the adherent contact of the liquid with the lower surface of the sheet. As said liquid reaches the liquid-overflow edges 71, the liquid starts to flow over said edges and discharges in the form of droplets or small streams through the holes 70. The liquid may either fall vertically downwardly in the receptacle 54, or it may leak over the lower surface of the guide plate untilthe lowest point thereof is reached, at which point the liquid may drip into the receptacle 54.

As the trailing edge of the sheet comes clear of the holes, the discharge of liquid through the holes is arrested, because there is no longer any moving surface which transports by adherent contact liquid to a level higher than the level 69 of the liquid in the container. Rollers 35 and 36 squeeze the sheet which is leaving the station, and they direct the sheet to the next station, in the present case the stabilizing station 26. It will be understood that the amount of liquid which is being discharged from the container is directly proportional to the size of the sheet, since it depends on the width of the sheet, the distance between the holes being sufficiently small, eg 2 cm, so as to permit a sufiiciently close approach of the actual width of the sheet, and on the length of the sheet which determines the time of discharge for a given transport speed.

The liquid which is being discharged is replaced continuously by fresh liquid from the bottle 29, whereby a constant liquid level in the container is maintained.

A modified embodiment of the arrangement of the grooves and the holes is shown in FIG. 5 where the grooves 67 of a guide plate 48 communicate through branch grooves with liquid-overflow edges 76 formed by openings 77.

In the operation of the apparatus, it may occur that the discharge of liquid over one or more overflow edges in the guide plate does not cease immediately when the trailing edge of the photographic sheet material moves upwardly, clear of the holes. On the contrary, the holes providing the said overflow edges remain filled up with liquid and liquid continues flowing out or dripping from the holes. Thus a liquid bead is formed in the grooves of the guide plate, which reaches from the level of the liquid in the container up to the holes in the guide plate. This kind of syphon efiect causes excess discharge and corresponding replenishment of the processing liquid. This effect is particularly occurring with the liquids in the activating and the stabilizing stations, since these processing liquids are mostly rather viscous and have good wetting properties.

The mentioned syphon effect may be overcomeby the provision of air passages which permit the air to rupture more easily the bead of liquid which tends to maintain.

A first embodiment of a guide plate which is provided with air passages is shown in FIGS. 6 and 7. Openended grooves or anti-siphoning air passages 80 are provided in the exit end of the guide plate 48 and they extend from theedge of the plate into the holes 70. The width of the grooves is somewhat smaller than the diameter of the holes. In the operation of the apparatus, the open grooves'80 are filled with processing liquid as the leading edge of a sheet passes over the grooves.

When the trailing edge of a sheet leaves the terminal edge of the guide plate, the liquid in the grooves 80. seeps back until the area of the holes 70 is reached. At that very moment the head of liquid in the holes is ruptured, the discharge of liquid over the liquid-overflow edges 73 provided by the holes ceases, and the liquid in the grooves 67 lowers until it reaches the level 69 of the liquid in the container.

An embodiment of the guide plate which is improved with respect to that of FIGS. 6 and 7 is shown in FIG. 8. The exit, edge of the guide plate 48 according to this figure is interrupted, to a much less extent, sinceronly one of every two grooves67 terminates into a cut-out portion which leads into open grooves 80, which, moreover, are tapered, The grooves 67 lead into holes providing liquid-overflow edges 73.

A sheet of photographic materialwhich is pulledover the edge of the plate as it is being gripped by the pair of rollers at the exit of the station is supported thereby over a greater distance. Such configuration of the slots may be desirable in case material must be treated which is very liable to damaging in one or more processing stations, e.g. in the activating and the stabilizing stations.

Still another embodiment of the air passages in the guide plate is shown in FIGS. 9 and 10. The air passages are in the form of terminal grooves 81 which continue the cut-out portions 70 at the lower side of the guide plate 48 until the exit edge thereof. The advantage of the present arrangement is that the exit edge of the concave, surface of the plate is in no way interrupted.

An other embodiment of the cut-out portions which determine the liquid-overflow edges is illustrated in FIGS. 11 to 13. A guide plate 48, the concave surface of which has grooves of a form as shown in FIG. 13 and represented diagrammatically by the draw lines in FIG. 12, is provided with recesses or notches 83 which extend into the plate from its exit end. The recesses have a trapezoid form, thesmaller parallel side 84 determining the liquid-overflow edge for the processing liquid. The grooves run at an angle of about 45 degrees with respect to the direction of motion of a sheet and they lead into the recesses according to a pitch which difi'ers from that of the recesses. As a consequence thereof the discharge of liquid over the edges 84 which are covered by a sheet may differ from one edge to an other.

Practice has proved that this produces no deleterious effect as to the uniformity of processing of a sheet. F urther it must be taken into account that in the described embodiment the longer parallel bases of the trapezoid recesses constitute quite an interruption of the edge of the guide plate so that this embodiment should preferably be used in stations wherein the treatment of a photographic material is not critical, in the present case, the fixing and the rinsing stations.

A particularity of the described embodiment is formed by the immersion plate 72. It may be seen that the convex surface of this plate determines a tapered gap or passage for a sheet through the container. The advantage thereof is that more processing liquid is available, in comparison with the apparatus according to FIG. 1, for the sheet as it starts travelling through the liquid in the container so that no difficulties can occasionally arise with processing liquid which becomes rapidly exhausted at its contact with a sheet material being processed. In addition, the widened passage may ensure a better agitation and renewal of the body of liquidv between the plates 48 and 72. A further feature of the plate 72 is the portion 86 of concave cross-section near its exit end. Thereby, the distance between the upper and the lower guide members for the sheet is locally increased in the area of the air passages, i.e. the recesses 83 in the plate 48, and it has been shown that such increased gap may avoid the establishment of liquid beads between the surface of the upper guide plate 72 and the corresponding area of the lower guide plate 48 comprising the concave surface and the recesses 83, after a sheet has moved through the station. Such liquid beads may cause difficulties in the processing of a next sheet some time after the processing of the first sheet, because the composition of the liquid of said beads is exaggeratedly exposed to the air oxygen. In addition, the presence of liquid beads between the recesses and the vupper guide plate may prevent the access of the overflow edges 84 to the air, as the trailing edge of a sheet moves clear of the edges, so that the discharge of liquid may continue, due to syphoning as already described hereinbefore.

So far, the operation of the apparatus has been described for the activating station only. It will be understood that the transport of a sheet through the stabilizing, fixing, and rinsing stations as well as the replenishment of liquid in these stations occur in a way similar as described for the activating station.

The apparatus according to the invention is not limited to the described embodiments.

The apparatus may also be used for carrying out the so-called stabilization process which requires only a highlyalkaline activator and a stabilizing solution to be applied to the exposed photographic material. There-' fore, the apparatus according ,to FIG. 1 may be provided with a part 88 which is pivotably connected at a point 89 and which serves to deflect when pivoted in an upwardly deflecting position as shown in broken lines in FIG. 1, photographic material towards the permanently fixed deflecting member 90 after having passed through the second station.

The apparatus may also be provided with means for improving the circulation of theprocessing liquid in the containers, and for that purpose a small circulation pump, such as the pump 91 in FIG. 1, may be provided in the lower part of the container. Such pump ensures moreover a more uniform temperature of the liquid in the container.

The rate of replenishment depends to some extent on the level of the liquid in the containers, and thus it is possible to control within certain limits the replenishment by removing or providing supplemental spacer rings 65 for the supply bottles.

We claim is:

1. Apparatus for processing photographic sheet material comprising:

1. a container for holding processing liquid,

2. means for keeping said container filled with liquid up to a predetermined level,

3. a guide plate in said container for guiding said material at least partially through said container and extending upwardly from a locus below the liquid level to an egress end spaced above the liquid level, said plate being formed with grooves therein and having a plurality of openings therethrough intermediate said liquid level and said egress end, each of said openings being in communication with at least one of said grooves, whereby liquid can overflow through said openings below the egress plate end,

4. means for advancing said sheet material through the container, and

5. immersion for constraining such sheet material to follow the guide plate at least over the upwardly extending portion thereof.

2. Apparatus according to claim 1 wherein said grooves are inclined transversely to the line of motion of a sheet of photographic material through the container.

3. Apparatus according to claim 1 wherein said openings are in the form of circular holes.

4. Apparatus according to claim 3 wherein antisiphoning air passages are provided adjacent the egress end of said guide plate, said passages communicating at one end with the atmosphere at a level above said holes and at the other with said holes to prevent the siphoning of liquid through said holes.

5. Apparatus according to claim 4 wherein said air passages are formed by terminal grooves extending from said holes to the egress end of the guide plate.

6. Apparatus according to claim 4 wherein said air passages are formed by slots extending from said holes to the egress end of the plate.

7. Apparatus according to claim 6 wherein said slots are tapered toward the egress end of the guide plate.

8. Apparatus according to claim 1 wherein said openings are formed by the lower end of a series of notches extending from the egress plate end toward the liquid level.

lected grooves communicate with said openings.

UNITEDISTATES PA'I' ENT OFFICE f 1; CERTIFICATE ()F'CORRECTION Patent No. 3,733,992 Dated May 22, 1973 Inventor) Emile Frans STIEVENART et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Heading of the Patent, under the @Eoreign Application Priority Data, insert September 2, 1970', Great Britain, 42.015 70 Column 8, Clairgi l, line 55, after "immerssion", insert Signed and sealed this 27th dayl'of November 1973.

(SEAL) Attest:

EDWARD M.-FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer 7 Acting Commissioner of Patents roan PQ-IQSO (10-69) 

1. Apparatus for processing photographic sheet material comprising:
 1. a container for holding processing liquid,
 2. means for keeping said container filled with liquid up to a predetermined level,
 3. a guide plate in said container for guiding said material at least partially through said container and extending upwardly from a locus below the liquid level to an egress end spaced above the liquid level, said plate being formed with grooves therein and having a plurality of openings therethrough intermediate said liquid level and said egress end, each of said openings being in communication with at least one of said grooves, whereby liquid can overflow through said openings below the egress plate end,
 4. means for advancing said sheet material through the container, and
 5. immersion for constraining such sheet material to follow the Guide plate at least over the upwardly extending portion thereof.
 2. means for keeping said container filled with liquid up to a predetermined level,
 2. Apparatus according to claim 1 wherein said grooves are inclined transversely to the line of motion of a sheet of photographic material through the container.
 3. Apparatus according to claim 1 wherein said openings are in the form of circular holes.
 3. a guide plate in said container for guiding said material at least partially through said container and extending upwardly from a locus below the liquid level to an egress end spaced above the liquid level, said plate being formed with grooves therein and having a plurality of openings therethrough intermediate said liquid level and said egress end, each of said openings being in communication with at least one of said grooves, whereby liquid can overflow through said openings below the egress plate end,
 4. means for advancing said sheet material through the container, and
 4. Apparatus according to claim 3 wherein anti-siphoning air passages are provided adjacent the egress end of said guide plate, said passages communicating at one end with the atmosphere at a level above said holes and at the other with said holes to prevent the siphoning of liquid through said holes.
 5. Apparatus according to claim 4 wherein said air passages are formed by terminal grooves extending from said holes to the egress end of the guide plate.
 5. immersion for constraining such sheet material to follow the Guide plate at least over the upwardly extending portion thereof.
 6. Apparatus according to claim 4 wherein said air passages are formed by slots extending from said holes to the egress end of the plate.
 7. Apparatus according to claim 6 wherein said slots are tapered toward the egress end of the guide plate.
 8. Apparatus according to claim 1 wherein said openings are formed by the lower end of a series of notches extending from the egress plate end toward the liquid level.
 9. Apparatus according to claim 8 wherein said notches increase in width towards the egress end of the plate.
 10. Apparatus according to claim 1 wherein said grooves communicate with said openings through branch grooves.
 11. Apparatus according to claim 1 wherein a receptacle is provided for collecting liquid discharging through the liquid-overflow openings.
 12. Apparatus according to claim 1 wherein said guide plate has a generally concave curvature.
 13. Apparatus according to claim 1 wherein only selected grooves communicate with said openings. 